超声波反射中的声阻抗

TNT 的一个关键特性是其熔点低，仅为 80.6 °C (177.1 °F)，远低于其 240 °C 的自燃温度。如此大的温差使得 TNT 能够安全地用蒸汽或热水熔化，并浇铸到弹药外壳中，这一过程称为熔铸。这使得生产致密、均匀且无裂纹的炸药成为可能。

用于氧燃料焊接的气瓶储存气体或其他工业或医用气体，压力非常高。压力调节器对于将气体减压至安全可用的工作压力至关重要。两级调节器分两步进行减压，即使气瓶压力因使用而下降，也能提供高度恒定的输送压力。这确保了稳定的流量，从而产生稳定的火焰，确保焊接质量始终如一。

发动机爆震，或称爆燃，是奥托循环发动机热效率的主要限制因素。虽然更高的压缩比可以提高效率，但也会导致压缩过程中空燃混合物的温度和压力升高。这可能导致混合物过早自燃，产生冲击波，发出“爆震”声，并可能损坏发动机。

The international standard for paper sizes, ISO 216 (e.g., A4, A3), is based on the square root of 2. The aspect ratio of every sheet is [latex]1:\sqrt{2}[/latex]. This unique property means that when a sheet is cut or folded in half parallel to its shorter sides, the resulting two smaller sheets have the exact same [latex]1:\sqrt{2}[/latex] aspect ratio as the original.

自働化（Jidoka）通常被翻译为“自动化”或“人性化的自动化”，是丰田生产系统的支柱之一。它授权任何机器或工人在检测到异常或缺陷时立即停止整条生产线。这可以防止大量生产缺陷产品，并立即发现问题，从而分析根本原因并找到永久性解决方案。

The separation factor, α (alpha), quantifies the selectivity of an extraction system for two different solutes, A and B. It is defined as the ratio of their individual distribution ratios, [latex]\alpha_{A,B} = \frac{D_A}{D_B}[/latex]. For a separation to be effective, α must be significantly different from unity. A larger α value implies an easier and more efficient separation.

The Log Mean Temperature Difference (LMTD) is the effective mean temperature difference for heat transfer in heat exchangers, particularly for counter-flow and parallel-flow arrangements. It is a logarithmic average of the temperature difference between the hot and cold fluids at each end. The LMTD is calculated using the formula: [latex]\Delta T_{LM} = \frac{\Delta T_A - \Delta T_B}{\ln(\Delta T_A / \Delta T_B)}[/latex].

回火脆化是指某些合金钢在特定温度范围内（约 375-575 °C）保温或缓慢冷却时，其韧性会降低。这种现象是由于杂质元素（例如磷、锡、锑）偏析至晶界，削弱了晶粒间的结合力，从而导致沿晶断裂。

For materials that do not have a distinct yield point on their stress-strain curve, like aluminum or high-strength steel, 'proof stress' is the engineering equivalent. It is defined as the stress required to produce a small, specified amount of permanent (plastic) deformation, typically 0.2% of the original gauge length. This value, [latex]\sigma_{0.2}[/latex], is used in design calculations as the material's practical elastic limit.

Fouling is the accumulation of unwanted material on heat transfer surfaces, which introduces an additional thermal resistance and degrades the performance of a heat exchanger. This fouling resistance ([latex]R_f[/latex]) reduces the overall heat transfer coefficient (U). The effect is quantified in the overall heat transfer equation: [latex]\frac{1}{U} = \frac{1}{h_i} + \frac{1}{h_o} + R_f + R_w[/latex].

Zyklon B was a trade name for a cyanide-based pesticide. Its active ingredient was hydrogen cyanide ([latex]HCN[/latex]), a highly volatile poison. The liquid HCN was adsorbed onto a porous solid carrier, such as diatomaceous earth or wood pulp discs. A stabilizer was added to prevent polymerization, and a warning agent, an eye irritant, was typically included for safety (deliberately removed from the commercial version for the mass murder version).

霍曼转移轨道机动是一种利用两次发动机点火将航天器从两个共面圆形轨道转移到另一个共面圆形轨道的轨道机动。它通常是燃料效率最高的双点火机动。转移轨道是一个椭圆，其远拱点和近拱点分别与初始轨道和最终轨道相切，因此需要一次点火进入椭圆轨道，另一次点火使其变为圆形轨道。